The Lawn Care Guide – May

Why my grass seed will not grow

Having scarified and aerated a back lawn, it was time to deal with bare patches and overseed. While grass seed germinates in most conditions the weather does need to be right. Soil temperature needs to be between 9 to 12 degrees Celsius.

Usually from March through until September is the best time to sow seed. Moisture is also needed, and we had plenty of that in March and April. But two sowings of fast-growing seed, once in March and again in April produced little or no result. 

The conclusion is the climate and soil has been too cold in our area. A ground thermometer test supported this theory because all other rules had been followed as usual. So we are waiting for much warmer weather before overseeding again and then it’s likely to be dry, so watering will be necessary. 

Other problems with the lawn at this time of the year will show up this month. Prolonged or heavy rainfall will have pointed to areas of standing water, where the ground may be compacted. Aeration and spiking will help with drainage and get air to the roots. 

Moss can be a problem in wet and shady areas of the lawn. Because moss reproduces by releasing thousands of spores, it needs to be dead before removing it. Ferrous sulphate in lawn sand kills it efficiently while the ammoniacal nitrogen helps to stimulate the growth of the grass plant. You simply water in the lawn sand and rake out the moss once it is blackened and dead. Any bare patches that are left can be seeded and (hopefully) will quickly germinate with the warmer spring weather. 

Weeds can be persistent this month as well so if you didn’t do a ‘weed and feed’ application in April it may be necessary to give the lawn an application of a selective weedkiller which can be done with a powered spreader or walk-behind pedestrian type. Those of you lucky enough to have a lawn growing lush, weed and moss free, will be lowering the deck on the garden tractor or adjusting the cutting height on the mower from now on.